基于周期极化LiTaO3晶体的高增益简并啁啾脉冲参量放大

根据准相位匹配理论计算了周期极化LiTaO₃(PPLT)晶体中0类准相位匹配过程(e+e→e)的增益曲线.在此基础上，使用数百μJ的低抽运能量获得了～10⁶的增益和～10.3%的转换效率，实现了中心波长位于1064nm的基于简并光学啁啾脉冲参量放大(OPCPA)技术的高增益放大，为产生超短超强激光脉冲提供了新的技术手段.实验结果与理论预期基本符合.     

1 kHz-0.1 TW高效率钛宝石激光放大器

介绍了一种高重复频率掺钛蓝宝石飞秒激光多通高效率放大系统.在抽运功率为23 W，入射功率为660 mW时，获得7.2 W的放大输出，放大效率达30%.经压缩器压缩后，获得单脉冲能量4.5 mJ,脉冲宽度为 38 fs，重复频率为1 kHz，峰值功率大于0.1 TW的超短超强激光脉冲. 关键词： 飞秒脉冲 高重复频率 啁啾脉冲放大     

Generation of near transform-limited ultrashort laser pulses in kilohertz chirped-pulse amplification system by compensating high order phase distortions

The effects of gain narrowing and high order dispersions on the pulse duration in our kilohertz chirped-pulse amplification system have been compensated experimentally. Using an acousto-optic programmable dispersive filter (AOPDF), the spectral full-width at half-maximum (FWHM) is expanded from 30 to 50 nm. Stable laser pulses with the duration of 30 fs (FWHM), which is 1.07 times Fourier-transform-limitation, have been acquired by pre-compensating the high order phase distortions using the phase measured by spectral phase interferometry for direct electric-field reconstruction (SPIDER).     

基于周期极化LiTaO3晶体的高增益简并啁啾脉冲参量放大

根据准相位匹配理论计算了周期极化LiTaO3(PPLT)体中0类准相位匹配过程(e+e→e)的增益曲线.在此基础上,使用数百μJ的低抽运能量获得了～106的增益和-10.3%的转换效率,实现了中心波长位于1064nm的基于简并光学啁啾脉冲参量放大(OPCPA)技术的高增益放大,为产生超短超强激光脉冲提供了新的技术手段.实验结果与理论预期基本符合.     

微机控制的红外光栅单色仪的定标

利用衍射光栅方程,分析可见光谱区标准光源的特征谱线的多级衍射特征,对标准光源的多级衍射进行计算机模拟计算,确定其多级衍射光强分布.测量汞灯特征谱线和He-Ne激光谱线的多级衍射谱分布,确定多级衍射谱的各级级次.对所得数据处理,做出拟合曲线,以多项式拟合方法求得拟合方程.以连续CO2激光器输出激光进行检测,同时以谱线分析仪监测,经过测量其波长,验证红外光栅单色仪定标准确.     

High and Stable Conversion Efficiency Obtaining in Single-Stage Multi-Crystal Optical Parametric Chirped Pulse Amplification System

An optical parametric chirped-pulse amplification system is demonstrated to provide 32.9% pump-to-signal conversion efficiency. Special techniques are used to make the signal and pump pulses match with each other in both spectral and temporal domains. The broadband 9.5-mJ pulses are produced at the repetition rate of 1 Hz with the gain of over 1.9×10^8. The output energy fluctuation of 7.8% is achieved for the saturated amplification process against the pump fluctuation of 10%.     

超声数字式相控阵换能器动态聚焦系统研制

本文是研制超声相控阵换能器动态聚焦系统,它包括数字式多通道信号发射系统和两种超声相控阵换能器。用数字式多通道信号发射系统产生多路数字信号,通 过改变每路信号的时延(相位),控制相控阵换能器的各个阵元,使它们发出的声束在空间某点聚焦。我们对这两种相控阵进行了实验测量,结果表明,用数字控 制的相控阵换能器,可以实现精密的动态聚焦,并可取得良好的聚焦效果。     

Pulse Compression by Filamentation in Argon with an Acoustic Optical Programmable Dispersive Filter for Predispersion Compensation

We have experimentally demonstrated pulses 0.4 mJ in duration smaller than 12 fs with an excellent spatial beam profile by self-guided propagation in argon. The original 52 fs pulses from the chirped pulsed amplification laser system are first precompressed to 32 fs by inserting an acoustic optical programmable dispersive filter instrument into the laser system for spectrum reshaping and dispersion compensation, and the pulse spectrum is subsequently broadened by filamentation in an argon cell. By using chirped mirrors for post-dispersion compensation, the pulses are successfully compressed to smaller than 12 fs.     

TEA13C16O2激光器的实验研究

为扩展可调谐TEA CO2激光器的输出波长范围，增加差分吸收雷达可探测的物质种类，采用^13C^16O2代替激光器工作气体中的CO2成分。计算了TEA^13C^16O2激光器在Ⅰ波段两个分支上的小信号增益系数分布。利用平面光栅单色仪，在小型快调谐TEA^13C^16O2激光器的Ⅰ波段共测到了32条谱线的能量输出，输出范围为10.663～11.347μm。与采用普通CO2作为工作气体的情况相比，激光器谱线输出范围在长波长方向上有很大扩展，输出的最长波长由CO2的10.74μm增大到11．347μm。测得TEA^13C^16O2激光器的最高输出能量为107mJ，并给出了Ⅰ波段典型谱线脉冲的半峰全宽。     

超短激光脉冲在不同色散参量光子晶体光纤中传输的数值模拟

为了使得数值模拟更为精确,采用广义非线性薛定谔方程(GNSE)描述超短激光脉冲在光子晶体光纤中的传输演化过程,并利用二阶分步傅里叶方法通过求解方程,数值计算了相同脉宽和能量的超短脉冲在不同色散参量的光子晶体光纤中非线性传输和超连续谱的产生。比较了超短脉冲在光纤不同色散区传输时,高阶色散和非线性效应对超连续谱的产生以及对脉冲波形演化的影响。结果表明,相对于超短脉冲中心波长位于光子晶体光纤的正常和反常色散区,可以相应获得短波波段和长波波段的超连续谱输出,当超短脉冲中心波长位于零色散波长点时,通过色散和非线性效应的联合作用,更易于产生全波长段的平坦超连续谱。